Comparison of a Commercial Real-Time PCR Assay for tcdB Detection to a Cell Culture Cytotoxicity Assay and Toxigenic Culture for Direct Detection of Toxin-Producing Clostridium difficile in Clinical Samples

摘要: Rapid detection of toxin-producing strains Clostridium difficile is essential for optimal management patients with C. infection. The BD GeneOhm (San Diego, CA) Cdiff assay, a real-time PCR assay that amplifies tcdB, was compared to cell culture neutralization (Wampole Toxin B [TOX-B] test; TechLab, Blacksburg, VA) and toxigenic culture. Using liquid (n = 273) soft 131) stool specimens from 377 symptomatic patients, all testing performed on the same day by independent laboratory staff according manufacturers' protocols. Toxigenic bacterial as follows. A 0.5-ml aliquot heated 80°C 10 min, followed inoculation onto modified cycloserine cefoxitin fructose agar without horse blood (Remel, Lenexa, KS) into prereduced chopped-meat broth. Of 404 tested, 340 were negative 40 positive (10.0% prevalence) both tcdB cytotoxin production. overall agreement between TOX-B test 94.8% (380/401). When used reference method, initial sensitivity, specificity, predictive values 90.9% (40/44), 95.2% (340/357), 70.2% (40/57), 98.8% (340/344), respectively. “gold standard,” 83.6%, 98.2%, 89.5%, 97.1%, respectively, those 67.2%, 99.1%, 93.2%, 94.4%, PCRs three samples inhibited upon testing; one sample resolved retesting. One produced nonspecific results. well standard directly fecal specimens.